Substrate processing apparatus, plurality of electrodes and method of manufacturing semiconductor device

ABSTRACT

There is provided a substrate processing apparatus, comprising: a reaction tube in which a substrate is processed; and a plurality of electrodes including a plurality of first electrodes to which a predetermined potential is applied and at least one second electrode to which a reference potential is applied. The at least one second electrode is arranged to be sandwiched between two sets of two or more continuously arranged electrodes of the plurality of first electrodes.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 16/558,506 filed Sep. 3, 2019 which is based uponand claims the benefit of priority from Japanese Patent Application No.2018-169453, filed on Sep. 11, 2018, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing apparatus, aplurality of electrodes, and a method of manufacturing a semiconductordevice.

BACKGROUND

As an example of processes of manufacturing a semiconductor device,substrate processing of forming or removing various films such as aninsulating film, a semiconductor film, a conductor film, and the like ona substrate is often carried out by loading a substrate into a processchamber of a substrate processing apparatus and supplying a precursorgas and a reaction gas into the process chamber.

In the case of a mass-produced device on which a fine pattern is formed,a temperature needs to be reduced in order to suppress diffusion ofimpurities and to enable the use of a material having low heatresistance such as an organic material.

Although substrate processing is generally performed by using plasma inorder to cope with such situation, when a plasma electrode is deformeddue to aging and heat from a heating device, the amount of activespecies such as ions or radicals generated by plasma may be reduced or avariation may occur in their generation distribution, making itdifficult to uniformly process a film while maintaining the capability.

SUMMARY

The present disclosure provides some embodiments of a technique capableof performing uniform substrate processing while maintaining acapability to generate active species by a plasma electrode.

According to one embodiment of the present disclosure, there is provideda technique, which includes: a reaction tube configured to form aprocess chamber in which a substrate is processed; an electrode fixingjig installed outside the reaction tube and configured to fix at leasttwo electrodes for forming plasma in the process chamber; and a heatingdevice installed outside the electrode fixing jig and configured to heatthe reaction tube, wherein the at least two electrodes include at leastone electrode to which a predetermined potential is applied and at leastone electrode to which a reference potential is applied, and wherein asurface area of the at least one electrode to which the predeterminedpotential is applied is two times or more than a surface area of the atleast one electrode to which the reference potential is applied.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a vertical type processfurnace of a substrate processing apparatus suitably used in anembodiment of the present disclosure, in which a portion of the processfurnace is shown in a vertical cross-sectional view.

FIG. 2 is a cross sectional view taken along line A-A in the substrateprocessing apparatus illustrated in FIG. 1.

FIG. 3A is a perspective view when electrodes according to an embodimentof the present disclosure are installed on a quartz cover, and FIG. 3Bis a view illustrating a positional relationship among a heater, aquartz cover, electrodes, projections for fixing the electrodes, and areaction tube according to an embodiment of the present disclosure.

FIG. 4A is a front view of an electrode according to an embodiment ofthe present disclosure, and FIG. 4B is a view illustrating that theelectrode is fixed to the quartz cover.

FIGS. 5A to 5E are views illustrating shapes of one electrode and acombination example of the electrode and a spacer using the electrode asa base according to an embodiment of the present disclosure, in whichFIG. 5A is an example of a flat electrode and a row of spacer, FIG. 5Bis an example of a flat electrode and two rows of spacers, FIG. 5C is anexample of a V-shaped electrode and a row of spacer, FIG. 5D is anexample of an inverse V-shaped electrode and two rows of spacers, andFIG. 5E is an example of a W-shaped electrode and two rows of spacers.

FIG. 6 is a schematic block diagram of a controller of the substrateprocessing apparatus illustrated in FIG. 1, in which an example of acontrol system of the controller is shown in a block diagram.

FIG. 7 is a flowchart illustrating an example of substrate processingusing the substrate processing apparatus illustrated in FIG. 1.

FIG. 8 is a diagram illustrating an equipotential distribution (curves)and an electric field distribution (arrows) in the case of using sixelectrodes according to an embodiment of the present disclosure, inwhich two sets of pairs of two hot electrodes to which a high-frequencypower source is connected via a matcher and the remaining groundelectrodes are alternately arranged.

FIG. 9 is a diagram illustrating an equipotential distribution (curves)and an electric field distribution (arrows) in the case of using sixelectrodes according to a comparative example of the embodiment of thepresent disclosure, in which three hot electrodes to which thehigh-frequency power source is connected via a matcher and three groundelectrodes are alternately arranged.

FIG. 10 is a diagram illustrating an equipotential distribution (curves)and an electric field distribution (arrows) in the case of using sixelectrodes according to an exemplary modification of the embodiment ofthe present disclosure, in which the remaining ground electrodes arearranged on both sides of one set of four hot electrodes to which thehigh-frequency power source is connected via a matcher.

DETAILED DESCRIPTION <An Embodiment of the Present Disclosure>

An embodiment of the present disclosure will now be described withreference to FIGS. 1 to 5E.

(1) Configuration of the Substrate Processing Apparatus (Heating Device)

As illustrated in FIG. 1, a process furnace 202 includes a heater 207 asa heating device (heating mechanism). The heater 207 has a cylindricalshape and is supported by a heater base (not shown) as a holding plateso as to be vertically installed. Further, the heater 207 is installedoutside a quartz cover 301 as an electrode fixing jig which will bedescribed later. The heater 207 functions as an activation mechanism (anexcitation part) configured to thermally activate (excite) a gas, asdescribed hereinbelow.

(Process Chamber)

The quartz cover 301 as the electrode fixing jig as describedhereinbelow is disposed inside the heater 207, and electrodes 300 of aplasma generating part as described hereinbelow is disposed inside thequartz cover 301. In addition, a reaction tube 203 is disposed insidethe electrodes 300 to be concentric with the heater 207. The reactiontube 203 is made of a heat resistant material, e.g., quartz (SiO₂),silicon carbide (SiC) or the like, and has a cylindrical shape with itsupper end closed and its lower end opened. A manifold 209 is disposedbelow the reaction tube 203 in a concentric relationship with thereaction tube 203. The manifold 209 is made of metal, e.g., stainlesssteel (SUS), and has a cylindrical shape with its upper and lower endsopened. The upper end of the manifold 209 engages with the lower end ofthe reaction tube 203. The manifold 209 is configured to support thereaction tube 203. An O-ring 220 a as a seal member is installed betweenthe manifold 209 and the reaction tube 203. The manifold 209 issupported by the heater base. Thus, the reaction tube 203 comes to be ina vertically mounted state. A process vessel (reaction vessel) is mainlyconfigured by the reaction tube 203 and the manifold 209. A processchamber 201 is formed in a hollow cylindrical portion of the processvessel. The process chamber 201 is configured to accommodate a pluralityof wafers 200 as substrates. The reaction tube 203 forms the processchamber 201 in which the wafers 200 are processed. The process vessel isnot limited to the aforementioned configuration, and only the reactiontube 203 may be referred to as the process vessel.

(Gas Supply Part)

Nozzles 249 a and 249 b are installed in the process chamber 201 so asto penetrate a sidewall of the manifold 209. Gas supply pipes 232 a and232 b are respectively connected to the nozzles 249 a and 249 b. In thismanner, two nozzles 249 a and 249 b and two gas supply pipes 232 a and232 b are installed in the process vessel and are capable of supplyingplural types of gases into the process chamber 201. Further, when onlythe reaction tube 203 is used as the process vessel, the nozzles 249 aand 249 b may be installed to penetrate a sidewall of the reaction tube203.

Mass flow controllers (MFCs) 241 a and 241 b, which are flow ratecontrollers (flow rate control parts), and valves 243 a and 243 b, whichare opening/closing valves, are respectively installed in the gas supplypipes 232 a and 232 b sequentially from the corresponding upstreamsides. Gas supply pipes 232 c and 232 d, which supply an inert gas, arerespectively connected to the gas supply pipes 232 a and 232 b at thedownstream sides of the valves 243 a and 243 b, respectively. MFCs 241 cand 241 d and valves 243 c and 243 d are respectively installed in thegas supply pipes 232 c and 232 d sequentially from the correspondingupstream sides.

The nozzles 249 a and 249 b are respectively disposed in a space with anannular plan-view shape between the inner wall of the reaction tube 203and the wafers 200 such that the nozzles 249 a and 249 b extend upwardalong an arrangement direction of the wafers 200 from a lower portion toan upper portion of the inner wall of the reaction tube 203. That is,the nozzles 249 a and 249 b are installed in a perpendicularrelationship with the surfaces (flat surfaces) of the wafers 200 at alateral side of the end portions (peripheral edge portions) of thewafers 200 which are carried into the process chamber 201. Gas supplyholes 250 a and 250 b for supplying a gas are installed on the sidesurfaces of the nozzles 249 a and 249 b, respectively. The gas supplyholes 250 a are opened toward the center of the reaction tube 203 so asto allow a gas to be supplied toward the wafers 200. The gas supplyholes 250 a and 250 b may be formed in a plural number between the lowerportion and the upper portion of the reaction tube 203.

As described above, in the present embodiment, a gas is transferredthrough the nozzles 249 a and 249 b, which are disposed in avertically-elongated space with an annular plan-view shape, i.e., acylindrical space, defined by the inner surface of the sidewall of thereaction tube 203 and the end portions (peripheral edge portions) of theplurality of the wafers 200 arranged within the reaction tube 203. Thegas is initially injected into the reaction tube 203, near the wafers200, through the gas supply holes 250 a and 250 b respectively formed inthe nozzles 249 a and 249 b. Accordingly, the gas supplied into thereaction tube 203 mainly flows in the reaction tube 203 in a directionparallel to surfaces of the wafers 200, i.e., in a horizontal direction.With this configuration, the gas can be uniformly supplied to therespective wafers 200. This makes it possible to improve the uniformityin the thickness of a film formed on each of the wafers 200. Inaddition, the gas flowing on the surfaces of the wafers 200 after thereaction, i.e., the reacted residual gas, flows toward an exhaust port,i.e., an exhaust pipe 231, which will be described later. The flowdirection of the residual gas is not limited to a vertical direction butmay be appropriately decided depending on a position of the exhaustport.

A precursor, which contains a predetermined element, for example, asilane precursor gas containing silicon (Si) as the predeterminedelement, is supplied from the gas supply pipe 232 a into the processchamber 201 via the MFC 241 a, the valve 243 a and the nozzle 249 a.

The silane precursor gas refers to a gaseous precursor, for example, agas obtained by vaporizing a silane precursor which remains in a liquidstate under a room temperature and an atmospheric pressure, or aprecursor such as silane precursor which remains in a gas state underthe room temperature and the atmospheric pressure. When the term“precursor” is used herein, it may refer to “a liquid precursorremaining in a liquid state,” “a precursor gas remaining in a gaseousstate,” or both.

As the silane precursor gas, it may be possible to use, for example, aprecursor gas containing Si and an amino group (amine group), i.e., anaminosilane precursor gas. The aminosilane precursor refers to a silaneprecursor having an amino group, and a silane precursor having an alkylgroup such as a methyl group, an ethyl group, a butyl group or the like.The aminosilane precursor is a precursor containing at least Si,nitrogen (N) and carbon (C). That is, the aminosilane precursor referredto herein may be said to be an organic precursor or may be said to be anorganic aminosilane precursor.

As the aminosilane precursor gas, it may be possible to use, forexample, a bis(tertiary-butylamino)silane (SiH₂[NH(C₄H₉)]₂,abbreviation: BTBAS) gas. The BTBAS gas may be said to be a precursorgas which contains one Si atom in one molecule and which has a Si—Nbond, an N—C bond or the like but does not have a Si—C bond. The BTBASgas acts as a Si source.

In the case of using a liquid precursor such as BTBAS which remains in aliquid state under a room temperature and an atmospheric pressure, theprecursor of a liquid state is vaporized by a vaporization system suchas a vaporizer, a bubbler or the like and is supplied as the silaneprecursor gas (the BTBAS gas or the like).

A reactant having a chemical structure different from that of theprecursor, for example, an oxygen (O)-containing gas, is supplied fromthe gas supply pipe 232 b into the process chamber 201 via the MFC 241b, the valve 243 b, and the nozzle 249 b.

The O-containing gas acts as an oxidizing agent (oxidizing gas), i.e.,an O source. As the O-containing gas, it may be possible to use, forexample, an oxygen (O₂) gas, water vapor (H₂O gas), or the like. In thecase of using the O₂ gas as the oxidizing gas, for example, this gas isplasma-excited using a plasma source as described hereinbelow, and issupplied as an excitation gas (O₂* gas).

An inert gas, for example, a nitrogen (N₂) gas, is supplied from the gassupply pipes 232 c and 232 d into the process chamber 201 via the MFCs241 c and 241 d, the valves 243 c and 243 d, and the nozzles 249 a and249 b.

A precursor supply system as a first gas supply system is mainlyconstituted by the gas supply pipe 232 a, the MFC 241 a, and the valve243 a. A reactant supply system as a second gas supply system is mainlyconstituted by the gas supply pipe 232 b, the MFC 241 b, and the valve243 b. An inert gas supply system is mainly constituted by the gassupply pipes 232 c and 232 d, the MFCs 241 c and 241 d, and the valves243 c and 243 d. The precursor supply system, the reactant supplysystem, and the inert gas supply system will be simply referred to as agas supply system (gas supply part) herein.

(Substrate Support)

As illustrated in FIG. 1, a boat 217 serving as a substrate support isconfigured to support a plurality of wafers 200, e.g., 25 to 200 wafers,in such a state that the wafers 200 are arranged in a horizontal postureand in multiple stages along a vertical direction with the centers ofthe wafers 200 aligned with one another. That is, the boat 217 isconfigured to arrange the wafers 200 in a spaced-apart relationship. Theboat 217 is made of a heat resistant material such as quartz or SiC.Heat insulating plates 218 made of a heat resistant material such asquartz or SiC are installed below the boat 217 in multiple stages. Withthis configuration, it is hard for heat generated from the heater 207 tobe transferred to a seal cap 219. However, the present embodiment is notlimited to this configuration. For example, instead of installing theheat insulating plates 218 below the boat 217, a heat insulating tube asa tubular member made of a heat resistant material such as quartz or SiCmay be installed under the boat 217.

(Plasma Generating Part)

Next, the plasma generating part will be described with reference toFIGS. 1 to 3B.

As illustrated in FIG. 2, plasma is generated in the reaction tube 203,which is a vacuum partition wall made of quartz or the like, usingcapacitively coupled plasma (CCP) when a reaction gas is supplied.

As illustrated in FIGS. 2 and 3A, the electrodes 300 are each configuredas a thin plate having an elongated rectangular shape in the arrangementdirection of the wafers 200. In the electrodes 300, first electrodes(hot electrodes) 300-1 to which a high-frequency power source 320 isconnected via a matcher (not shown) and second electrodes (groundelectrodes) 300-2 grounded to a reference potential of 0 V are arrangedat equal intervals. In the present disclosure, when there is no need tospecially distinguish and describe the electrodes, they will bedescribed as the electrodes 300.

The electrodes 300 are arranged between the reaction tube 203 and theheater 207 in a substantially arc shape along the outer wall of thereaction tube 203, and are fixedly arranged on the inner wall surface ofthe quartz cover, which will be described later, formed in an arc shapehaving a central angle of, e.g., 30 degrees or more and 240 degrees orless. When the central angle is set less than 30 degrees, a plasmageneration amount may be reduced. Further, when the central angle is setat an angle of more than 240 degrees, the heat energy from the heater207 is interrupted, which may adversely affect wafer processing. Inaddition, when the central angle is set at an angle of more than 240degrees, it is difficult to dispose the nozzles 249 a and 249 b and atemperature sensor 263, for example, a cascade thermocouple (TC), byavoiding a plasma generation region. For example, when the nozzles 249 aand 249 b and the like are disposed in the plasma generation region,particles (PC) are likely to be generated from the nozzles 249 a and 249b and the like. Similarly, when the cascade TC is disposed in the plasmageneration region, a discharge will occur from the TC line, resulting indamage to the wafers 200 or non-uniformity of a film. Therefore, bysetting the central angle at 30 degrees or more and 240 degrees or less,it is possible to perform the wafer processing while avoidinginterruption of the heat energy from the heater 207 and securing theplasma generation amount. Plasma active species 302 are generated in thereaction tube 203 by inputting a high frequency of, e.g., 13.56 MHz,from the high-frequency power source 320 to the electrodes 300 via thematcher (not shown). By the plasma thus generated, it is possible tosupply the plasma active species 302 for substrate processing from theperiphery of the wafers 200 to the surface of the wafers 200. The plasmagenerating part is mainly constituted by the electrodes 300 and thehigh-frequency power source 320. The plasma generating part may beconsidered as including the matcher (not shown) and the quartz cover 301as the electrode fixing jig as described hereinbelow.

The electrodes 300 may be made of metal such as aluminum, copper,stainless steel or the like but may be made of an oxidation resistantmaterial such as nickel, making it possible to perform the substrateprocessing while avoiding the deterioration of electric conductivity. Inparticular, the electrodes 300 are made of a nickel alloy material towhich aluminum is added to form an AlO film, which is an oxide filmhaving high heat resistance and corrosion resistance, on the surface ofthe electrodes. Since deterioration process of the electrodes can beavoided by the effect of such film formation, it is possible to avoid areduction in plasma generation efficiency due to a reduction in theelectric conductivity.

In addition, as illustrated in FIG. 4A, the electrode 300 has a notchportion 305 constituted by a circular notch portion 303 through which aprojection head 311 as described hereinbelow passes and a slide notchportion 304 to which a projection shaft portion 312 slides.

The electrode 300 may be configured to have a range of a thickness of0.1 mm or more and 1 mm or less and a width of 5 mm or more and 30 mm orless in some embodiments so as to have a sufficient strength withoutsignificantly reducing the efficiency of wafer heating by a heat source.FIGS. 5A and 5B illustrate an example using an electrode 300 having aflat structure, and FIGS. 5C to 5E illustrate an example using anelectrode 300 having a bending structure as a deformation suppressingpart for preventing deformation due to heating of the heater 207. Sincethe electrodes 300 are arranged between the quartz reaction tube 203 andthe heater 207, a bending angle of 90 to 175 degrees is suitable due toa space limit. It is necessary to be careful of over-bending because theelectrode surface has a film formed by thermal oxidation, which may bedelaminated due to thermal stress to generate particles. Furthermore,the example of FIG. 5E having a bending structure at three positions isparticularly suitable for use in a high temperature zone because it isresistant to deformation by twisting.

In a vertical type substrate processing apparatus, the frequency of thehigh-frequency power source 320 is set to 13.56 MHz, and an electrodehaving a length of 1 m, a width of 10 mm, and a thickness of 1 mm isadopted. As illustrated in FIG. 3B, the first electrodes 300-1 to whicha plurality of arbitrary potentials are applied with an electrode pitch(center-to-center distance) of 20 mm and the second electrodes 300-2 towhich a reference potential is applied are arranged on the outer wall ofthe reaction tube having a tube shape in the order of the firstelectrode 300-1, the first electrode 300-1, the second electrode 300-2,the first electrode 300-1, the first electrode 300-1, . . . , togenerate plasma of a CCP mode. That is, in the electrodes 300, two firstelectrodes 300-1 are continuously arranged and one second electrode300-2 is arranged to be sandwiched between two sets of continuouslyarranged first electrodes 300-1.

An equipotential distribution (curves) and an electric fielddistribution (arrows) formed in the process chamber 201 in the case ofusing six electrodes 300 will be described with reference to FIGS. 8 to10. FIG. 8 is a diagram illustrating an equipotential distribution(curves) and an electric field distribution (arrows) when two sets ofhot electrodes 300-1, each set having two electrodes, to which apotential of 50 V is applied, and two ground electrodes 300-2 arealternately arranged (embodiment). FIG. 9 is a diagram illustrating anequipotential distribution (curves) and an electric field distribution(arrows) when three hot electrodes 300-1, to which a potential of 50 Vis applied, and three ground electrodes 300-2 are alternately arranged(comparative example). FIG. 10 is a diagram illustrating anequipotential distribution (curves) and an electric field distribution(arrows) when two ground electrodes 300-2 are arranged on both sides ofone set of four hot electrodes 300-1 to which a potential of 50 V isapplied (modification).

Since an energy of 15.58 eV or more is required to ionize an N₂ gas suchthat the N₂ gas become N₂ ⁺, it can be seen that the embodiment of FIG.8 has the widest region 340 of potential equal to or greater than 20 Vand the modification of FIG. 10 has the second widest region 340 ofpotential equal to or greater than 20 V, for example, when the regions340 of potential equal to or greater than 20 V are compared. That is,the embodiment of FIG. 8 means that the plasma generation amount or theplasma generation efficiency is the highest, and a total surface area ofthe hot electrodes 300-1 is twice a total surface area of the groundelectrodes 300-2. In the modification of FIG. 10, a total surface areaof the hot electrodes 300-1 is twice a total surface area of the groundelectrodes 300-2. In the comparative example of FIG. 9, a total surfacearea of the hot electrodes 300-1 is equal to a total surface area of theground electrodes 300-2. The total surface area of the hot electrodes300-1 may be two times or more and three times or less than the totalsurface area of the ground electrodes 300-2 in some embodiments. Inaddition, when the total surface area of the hot electrodes 300-1 isless than two times the total surface area of the ground electrodes300-2, since a spread of the potential distribution is narrow, theplasma generation efficiency may be low. Further, when the total surfacearea of the hot electrodes 300-1 exceeds three times the total surfacearea of the ground electrodes 300-2, the potential distribution spreadsto the edge portion of the wafers 200, and the wafers 200 become anobstacle, resulting in saturation in the plasma generation efficiency.In this state, the edge portion of the wafers 200 is also discharged andthe wafers 200 may be easily damaged. In addition, since current flowingthrough the ground electrodes 300-2 is a multiple of the surface area ofthe hot electrodes, Joule heat may be generated at a high temperature.In this state, films of different qualities are formed on the surface ofthe wafers 200 and the edge portion of the wafers 200, which makes itdifficult to ensure in-plane uniformity. When the total surface area ofthe hot electrodes 300-1 is two times or more and three times or lessthe total surface area of the ground electrodes 300-2, it is possible torealize high plasma generation efficiency while preventing the damage tothe wafers 200 or the non-uniformity of films on the surface of thewafers 200 described above. However, it should be noted that theequipotential distribution and electric field distribution describedabove are a state before the plasma is generated, and when the plasma isgenerated, these distributions are greatly distorted due to a Debyeshielding effect, and the space potential of the plasma is around 0 V.

An internal pressure of the furnace during the substrate processing maybe controlled in a range of 10 Pa or more and 300 Pa or less in someembodiments. This is because, when the internal pressure of the furnaceis lower than 10 Pa, a mean free path of gas molecules becomes longerthan a Debye length of the plasma and the plasma directly making contactwith the furnace wall becomes prominent, thus making it difficult tosuppress the generation of particles. In addition, this is because, whenthe internal pressure of the furnace is higher than 300 Pa, since theplasma generation efficiency is saturated, the plasma generation amountdoes not change even if the reaction gas is supplied, and the reactiongas is unnecessarily consumed and at the same time, the transferefficiency of plasma active species to the wafers degrades as the meanfree path of the gas molecules becomes shorter.

(Electrode Fixing Jig)

Next, the quartz cover 301 as an electrode fixing jig for fixing theelectrode 300 will be described with reference to FIGS. 3A to 4B. Asillustrated in FIGS. 3A, 3B, 4A, and 4B, the plurality of installedelectrodes 300 are hooked on projections 310 installed on an inner wallsurface of the quartz cover 301 as the electrode fixing jig having acurved shape at its notch portion 305 are fixed by sliding, are unitized(hook type electrode unit) to be integrated with the quartz cover 301,and are installed on the outer periphery of the reaction tube 203. Theelectrodes 300 and the quartz cover 301 as the electrode fixing jig willbe generally referred herein to as an electrode fixing unit. The quartzcover 301 and the electrodes 300 are made of materials such as quartzand a nickel alloy, respectively.

The quartz cover 301 may be configured to have a range of a thickness of1 mm or more and 5 mm or less in some embodiments so as to have asufficient strength without significantly reduce the efficiency of waferheating by the heater 207. When the thickness of the quartz cover 301 isless than 1 mm, the quartz cover 301 cannot obtain a predeterminedstrength against its own weight or temperature change, and when it isconfigured to be larger than 5 mm, since the heat energy emitted fromthe heater 207 is absorbed, the wafers 200 cannot be properlyheat-treated.

Furthermore, the quartz cover 301 has a plurality of projections 310 asa hook-shaped fixing portion for fixing the electrodes 300 on the innerwall surface on the reaction tube side. The projections 310 are eachconfigured by the projection head 311 and the projection shaft portion312. A maximum width of the projection head 311 is smaller than adiameter of the circular notch portion 303 of the notch portion 305 ofthe electrode 300, and a maximum width of the projection shaft portion312 is smaller than a width of the slide notch portion 304. The notchportion 305 of the electrode 300 is shaped like a keyhole, and the slidenotch portion 304 can guide the projection shaft portion 312 whensliding, and the projection head 311 has a structure that does not comeoff the slide notch portion 304. That is, it can be said that, theelectrode fixing jig has a fixing portion having the projection head 311which is a leading end portion that prevents the electrodes 300 fromcoming off the projection shaft portion 312 as a columnar portion towhich the electrodes 300 are hooked. It is also apparent that the shapesof the notch portion 305 and the projection head 311 described above arenot limited to the shapes illustrated in FIGS. 3A, 3B, 4A and 4B as longas the electrode 300 can be hooked to the quartz cover 301. For example,the projection head 311 may have a convex shape such as a hammer or aspike.

In order to keep the distance between the quartz cover 301 or thereaction tube 203 and the electrode 300 constant, an elastic body suchas a spacer or a spring may be included in the quartz cover 301 or theelectrode 300 therebetween and the spacer may have a structureintegrated with the quartz cover 301 or the electrode 300.

In the preset embodiment, a spacer 330 as illustrated in FIG. 4B has astructure integrated with the quartz cover 301. A plurality of spacers330 for one electrode are effective in fixing the distance constant.

In order to obtain high substrate processing capability at a substratetemperature of 500 degrees C. or lower, the occupancy rate of the quartzcover 301 may be set to a substantially arc shape having a central angleof 30 degrees or more and 240 degrees or less in some embodiments.Further, in order to avoid the generation of particles, an arrangementthat avoids the exhaust pipe 231, which is an exhaust port, the nozzles249 a and 249 b, or the like may be possible in some embodiments. Thatis, the quartz cover 301, which is the electrode fixing jig, is disposedon an outer periphery of the reaction tube 203 other than positions atwhich the nozzles 249 a and 249 b, which are a gas supply part installedin the reaction tube 203, and the exhaust tube 231, which is a gasexhaust part, are installed. In the present embodiment, two quartzcovers 301 having a central angle of 110 degrees are installed inbilateral symmetry.

(Spacer)

Next, the spacer 330 for fixing the electrode 300 at a certain distanceaway from the surface of the quartz cover 301 as the electrode fixingjig or the outer wall of the reaction tube 203 is illustrated in FIGS.4A and 4B.

For example, the spacer 330 is integrated with the quartz cover 301 witha columnar quartz material and is configured to make contact with theelectrode so that the electrode 300 is fixed to the quartz cover 301. Anexample of a combination of the flat electrode 300 and a row of spacer330 is illustrated in FIG. 5A, and an example of a combination of theelectrode 300 of the same shape and two rows of spacers 330 isillustrated in FIG. 5B. When it is desired to strengthen the fixation ofthe electrode 300, as illustrated in FIGS. 5C to 5E, the spacers 330 maybe arranged so that the spacers 330 are located at V-shaped valleys ofbent portions of the electrode 300 in some embodiments. Without beinglimited to the aforementioned configuration, the spacers 330 may beintegrated with either the electrode 300 or the quartz cover 301regardless of a shape, as long as the electrode 300 may be fixed to thequartz cover 301 or the reaction tube 203 at a fixed distance. Forexample, the spacers 330 may be integrated with the quartz cover with asemi-cylindrical quartz material to fix the electrode 300, or thespacers 330 may be integrated with the electrode as a metal plate suchas stainless steel (SUS) or the like to fix the electrode 300. Since theelectrode fixing jig and the spacers are installed on the quartz cover,positioning of the electrode is facilitated, and since only theelectrode can be replaced when it is deteriorated, the cost is reduced.Furthermore, since the spacers 330 generate a pressing force in onedirection of the projection head 311 as the leading end portiondescribed above via the surface making contact with the electrode 300,the electrode 300 is prevented from being deviated from the quartz cover301. In the present disclosure, the spacers 330 may be included in theelectrode fixing unit described above.

(Exhaust Part)

As illustrated in FIG. 1, the exhaust pipe 231 configured to exhaust aninternal atmosphere of the process chamber 201 is installed in thereaction tube 203. A vacuum pump 246 as a vacuum exhaust device isconnected to the exhaust pipe 231 via a pressure sensor 245 as apressure detector (pressure detection part), which detects the internalpressure of the process chamber 201, and an auto pressure controller(APC) valve 244 as an exhaust valve (pressure regulation part). The APCvalve 244 is configured so that a vacuum exhaust of the interior of theprocess chamber 201 and a vacuum exhaust stop can be performed byopening and closing the APC valve 244 while operating the vacuum pump246 and the internal pressure of the process chamber 201 can be adjustedby adjusting an opening degree of the APC valve 244 based on pressureinformation detected by the pressure sensor 245 while operating thevacuum pump 246. An exhaust system is mainly constituted by the exhaustpipe 231, the APC valve 244, and the pressure sensor 245. The vacuumpump 246 may be regarded as being included in the exhaust system. Theexhaust pipe 231 is not limited to being installed in the reaction tube203 but may be installed in the manifold 209 just like the nozzles 249 aand 249 b.

(Peripheral Device)

A seal cap 219, which serves as a furnace opening cover configured tohermetically seal a lower end opening of the manifold 209, is installedunder the manifold 209. The seal cap 219 is configured to make contactwith the lower end of the manifold 209 at a lower side in the verticaldirection. The seal cap 219 is made of metal such as, e.g., stainlesssteel (SUS) or the like, and is formed in a disc shape. An O-ring 220 b,which is a seal member making contact with the lower end portion of themanifold 209, is installed on an upper surface of the seal cap 219.

A rotation mechanism 267 configured to rotate the boat 217 is installedat the opposite side of the seal cap 219 from the process chamber 201. Arotary shaft 255 of the rotation mechanism 267, which penetrates theseal cap 219, is connected to the boat 217. The rotation mechanism 267is configured to rotate the wafers 200 by rotating the boat 217. Theseal cap 219 is configured to be vertically moved up and down by a boatelevator 115 which is an elevator mechanism vertically installed outsidethe reaction tube 203. The boat elevator 115 is configured to load andunload the boat 217 into and from the process chamber 201 by moving theseal cap 219 up and down.

The boat elevator 115 is configured as a transfer device (transfermechanism) which transfers the boat 217, i.e., the wafers 210, into andout of the process chamber 201. In addition, a shutter 219 s as afurnace opening cover capable of hermetically sealing the lower endopening of the manifold 209 is installed under the manifold 209 whilemoving the seal cap 219 down with the boat elevator 115. The shutter 219s is made of metal such as, e.g., stainless steel (SUS) or the like, andis formed in a disc shape. An O-ring 220 c, which is a seal membermaking contact with the lower end portion of the manifold 209, isinstalled on an upper surface of the shutter 219 s. An opening/closingoperation (an up-down movement operation or a rotational movementoperation) of the shutter 219 s is controlled by a shutteropening/closing mechanism 115 s.

A temperature sensor 263 serving as a temperature detector is installedin the reaction tube 203. Based on temperature information detected bythe temperature sensor 263, a state of supplying electric power to theheater 207 is adjusted such that the interior of the process chamber 201has a desired temperature distribution. The temperature sensor 263 isinstalled along the inner wall of the reaction tube 203 just like thenozzles 249 a and 249 b.

(Control Device)

Next, a control device will be described with reference to FIG. 7. Asillustrated in FIGS. 6 and 7, a controller 121, which is a control part(control device), may be configured as a computer including a centralprocessing unit (CPU) 121 a, a random access memory (RAM) 121 b, amemory device 121 c, and an I/O port 121 d. The RAM 121 b, the memorydevice 121 c, and the I/O port 121 d are configured to exchange datawith the CPU 121 a via an internal bus 121 e. An input/output device 122formed of, for example, a touch panel or the like, is connected to thecontroller 121.

The memory device 121 c is constituted by, for example, a flash memory,a hard disk drive (HDD), or the like. A control program for controllingoperations of a substrate processing apparatus, a process recipe forspecifying sequences and conditions of a film-forming process asdescribed hereinbelow, or the like is readably stored in the memorydevice 121 c. The process recipe functions as a program for causing thecontroller 121 to execute each sequence in various processes (thefilm-forming process), as described hereinbelow, to obtain apredetermined result. Hereinafter, the process recipe and the controlprogram will be generally and simply referred to as a “program.”Furthermore, the process recipe will be simply referred to as a“recipe.” When the term “program” is used herein, it may indicate a caseof including only the recipe, a case of including only the controlprogram, or a case of including both the recipe and the control program.The RAM 121 b is configured as a memory area (work area) in which aprogram, data or the like read by the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the MFCs 241 a to 241 d, the valves243 a to 243 d, the pressure sensor 245, the APC valve 244, the vacuumpump 246, the heater 207, the temperature sensor 263, the rotationmechanism 267, the boat elevator 115, the shutter opening/closingmechanism 115 s, the high-frequency power source 320, and the like, asdescribed above.

The CPU 121 a is configured to read the control program from the memorydevice 121 c and execute the same. The CPU 121 a also reads the recipefrom the memory device 121 c according to an input of an operationcommand from the input/output device 122. In addition, the CPU 121 a isconfigured to control, according to the contents of the recipe thusread, the operation of the rotation mechanism 267, flow rate adjustingoperation of various kinds of gases by the MFCs 241 a to 241 d,opening/closing operation of the valves 243 a to 243 d, opening/closingoperation of the APC valve 244, pressure regulating operation performedby the APC valve 244 based on the pressure sensor 245, driving andstopping of the vacuum pump 246, temperature adjusting operationperformed by the heater 207 based on the temperature sensor 263,operation of normal or reverse rotating the boat 217 with the rotationmechanism 267 and adjusting the rotation angle and the rotation speed ofthe boat 217, operation of moving the boat 217 up and down with the boatelevator 115, operation of opening and closing the shutter 219 s withthe shutter opening/closing mechanism 115 s, power supply to thehigh-frequency power source 320, and the like.

The controller 121 may be configured by installing, on the computer, theaforementioned program stored in an external memory device 123 (forexample, a magnetic disc such as a hard disk, an optical disc such as aCD, a magneto-optical disc such as an MO, or a semiconductor memory suchas a USB memory). The memory device 121 c or the external memory device123 is configured as a computer-readable recording medium. Hereinafter,the memory device 121 c and the external memory device 123 will begenerally and simply referred to as a “recording medium.” When the term“recording medium” is used herein, it may indicate a case of includingonly the memory device 121 c, a case of including only the externalmemory device 123, or a case of including both the memory device 121 cand the external memory device 123. Furthermore, the program may besupplied to the computer using a communication means such as theInternet or a dedicated line, instead of using the external memorydevice 123.

(2) Substrate Processing

A process example of forming a film on a substrate using theaforementioned substrate processing apparatus, which is one of theprocesses for manufacturing a semiconductor device, will be describedwith reference to FIG. 7. In the following descriptions, the operationsof the respective parts constituting the substrate processing apparatusare controlled by the controller 121.

In the present disclosure, for the sake of convenience, a film-formingsequence illustrated in FIG. 7 may sometimes be denoted as follows. Thesame denotation will be used in the modifications and other embodimentsas described hereinbelow.

(BTBAS→O₂*)×n⇒SiO

When the term “wafer” is used herein, it may refer to a wafer itself ora laminated body of a wafer and a predetermined layer or film formed onthe surface of the wafer. In addition, when the phrase “a surface of awafer” is used herein, it may refer to a surface of a wafer itself or asurface of a predetermined layer or the like formed on a wafer.Furthermore, in the present disclosure, the expression “a predeterminedlayer is formed on a wafer” may mean that a predetermined layer isdirectly formed on a surface of a wafer itself or that a predeterminedlayer is formed on a layer or the like formed on a wafer. In addition,when the term “substrate” is used herein, it may be synonymous with theterm “wafer.”

(Loading Step: S1)

A plurality of wafers 200 is charged on the boat 217 (wafer charging),and the shutter 219 s is moved by the shutter opening/closing mechanism115 s to open the lower end opening of the manifold 209 (shutteropening). Thereafter, as illustrated in FIG. 1, the boat 217 supportingthe plurality of wafers 200 is lifted up by the boat elevator 115 and isloaded into the process chamber 201 (boat loading). In this state, theseal cap 219 seals the lower end of the manifold 209 through the O-ring220 b.

(Pressure Regulation and Temperature Adjustment Step: S2)

The interior of the process chamber 201 is vacuum-exhausted(depressurization-exhausted) by the vacuum pump 246 so as to reach adesired pressure (degree of vacuum). In this operation, the internalpressure of the process chamber 201 is measured by the pressure sensor245. The APC valve 244 is feedback-controlled based on the measuredpressure information (pressure regulation). The vacuum pump 246 maycontinue operating normally at least until a film-forming step asdescribed hereinbelow is completed.

Furthermore, the interior of the process chamber 201 is heated by theheater 207 to a desired temperature. In this operation, the state ofsupplying electric power to the heater 207 is feedback-controlled basedon the temperature information detected by the temperature sensor 263such that the interior of the process chamber 201 has a desiredtemperature distribution (temperature adjustment). The heating of theinterior of the process chamber 201 by the heater 207 may becontinuously performed at least until the film-forming step as describedhereinbelow is completed. However, when the film-forming step isperformed under a temperature condition lower than a room temperature,the heating of the interior of the process chamber 201 by the heater 207may not be performed. In addition, when only the processing under thistemperature is performed, the heater 207 is not necessary and may not beinstalled in the substrate processing apparatus. In this case, theconfiguration of the substrate processing apparatus can be simplified.

Subsequently, the rotation of the boat 217 and the wafers 200 by therotation mechanism 267 begins. The rotation of the boat 217 and thewafers 200 by the rotation mechanism 267 may be continuously performedat least until the film-forming step as described hereinbelow iscompleted.

(Film-Forming Step: S3, S4, S5, and S6)

Thereafter, the film-forming step is performed by sequentially executingsteps S3, S4, S5, and S6.

(Precursor Gas Supply Step: S3 and S4)

At step S3, a BTBAS gas is supplied to the wafer 200 in the processchamber 201.

The valve 243 a is opened to allow the BTBAS gas to flow through the gassupply pipe 232 a. The flow rate of the BTBAS gas is adjusted by the MFC241 a. The BTBAS gas is supplied from the gas supply holes 250 a intothe process chamber 201 via the nozzle 249 a and is exhausted from theexhaust pipe 231. At this time, the BTBAS gas is supplied to the wafer200. Simultaneously, the valve 243 c is opened to allow an N₂ gas toflow through the gas supply pipe 232 c. The flow rate of the N₂ gas isadjusted by the MFC 241 c. The N₂ gas is supplied into the processchamber 201 together with the BTBAS gas and is exhausted from theexhaust pipe 231.

Furthermore, in order to prevent the BTBAS gas from entering the nozzle249 b, the valve 243 d is opened to allow the N₂ gas to flow through thegas supply pipe 232 d. The N₂ gas is supplied into the process chamber201 via the gas supply pipe 232 d and the nozzle 249 b and is exhaustedfrom the exhaust pipe 231.

The supply flow rate of the BTBAS gas controlled by the MFC 241 a may beset at a flow rate which falls within a range of, for example, 1 sccm ormore and 2,000 sccm or less, or 10 sccm or more and 1,000 sccm or lessin some embodiments. The supply flow rates of the N₂ gas controlled bythe MFCs 241 c and 241 d may be respectively set at a flow rate whichfalls within a range of, for example, 100 sccm or more and 10,000 sccmor less. The internal pressure of the process chamber 201 may be set ata pressure which falls within a range of, for example, 1 Pa or more and2,666 Pa or less, or 67 Pa or more and 1,333 Pa or less in someembodiments. The time, during which the BTBAS gas is supplied to thewafer 200, may be set at a time period which falls within a range of,for example, 1 second or more and 100 seconds or less, or 1 second ormore and 50 seconds or less in some embodiments. The temperature of theheater 207 is set such that the temperature of the wafer 200 (firsttemperature) becomes a temperature which falls within a range of, forexample, 0 degree C. or higher and 150 degrees C. or lower, or a roomtemperature (25 degrees C.) or higher and 100 degrees C. or lower insome embodiments, or 40 degrees C. or higher and 90 degrees C. or lowerin some embodiments.

By supplying the BTBAS gas to the wafer 200 under the aforementionedconditions, a Si-containing layer is formed on (a base film of thesurface of) the wafer 200. The Si-containing layer may be a Si layer, anadsorption layer (a chemisorption layer or a physisorption layer) ofBTBAS, or may include both of them.

After the Si-containing layer is formed, the valve 243 a is closed tostop the supply of the BTBAS gas into the process chamber 201. At thistime, the interior of the process chamber 201 is vacuum-exhausted by thevacuum pump 246 while opening the APC valve 244. Thus, the unreactedBTBAS gas, the BTBAS gas contributed to the formation of theSi-containing layer, or the reaction byproduct remaining within theprocess chamber 201 is removed from the interior of the process chamber201 (S4). Furthermore, the supply of the N₂ gas into the process chamber201 is maintained while opening the valves 243 c and 243 d. The N₂ gasacts as a purge gas. The precursor gas supply step may not include thestep S4.

As the precursor gas, it may be possible to use, in addition to theBTBAS gas, a tetrakis-dimethylaminosilane (Si[N(CH₃)₂]₄, abbreviation:4DMAS) gas, a tris-dimethylaminosilane (Si[N(CH₃)₂]₃H, abbreviation:3DMAS) gas, a bis-dimethylaminosilane (Si[N(CH₃)₂]₂H₂, abbreviation:BDMAS) gas, a bis-diethylaminosilane (Si[N(C₂H₅)₂]₂H₂, abbreviation:BDEAS) gas, or the like in some embodiments. In addition, as theprecursor gas, it may be possible to use various kinds of aminosilaneprecursor gases such as a dimethylaminosilane (DMAS) gas, adiethylaminosilane (DEAS) gas, a dipropylaminosilane (DPAS) gas, adiisopropylaminosilane (DIPAS) gas, a butylaminosilane (BAS) gas, ahexamethyldisilazane (HMDS) gas and the like, an inorganic halosilaneprecursor gas such as a monochlorosilane (SiH₃Cl, abbreviation: MCS)gas, a dichlorosilane (SiH₂Cl₂, abbreviation: DCS) gas, atrichlorosilane (SiHCl₃, abbreviation: TCS) gas, a tetrachlorosilane,i.e., silicon tetrachloride (SiCl₄, abbreviation: STC) gas, ahexachlorodisilane (Si₂Cl₆, abbreviation: HCDS) gas, anoctachlorotrisilane (Si₃Cl₈, abbreviation: OCTS) gas or the like, or ahalogen-group-free inorganic silane precursor gas such as a monosilane(SiH₄, abbreviation: MS) gas, a disilane (Si₂H₆, abbreviation: DS) gas,a trisilane (Si₃H₈, abbreviation: TS) gas or the like in someembodiments.

As the inert gas, it may be possible to use, in addition to the N₂ gas,a rare gas such as an Ar gas, an He gas, an Ne gas, a Xe gas or thelike.

(Reaction Gas Supply Step: S5 and S6)

After the film-forming process is completed, a plasma-excited O₂ gas asa reaction gas is supplied to the wafer 200 in the process chamber 201(S5).

At this step, the opening/closing control of the valves 243 b to 243 dis performed in the same procedure as the opening/closing control of thevalves 243 a, 243 c and 243 d at step S3. The flow rate of the O₂ gas iscontrolled by the MFC 241 b. The O₂ gas is supplied from the gas supplyholes 250 b into the process chamber 201 via the nozzle 249 b. At thistime, high-frequency power (frequency 13.56 MHz in the presentembodiment) is supplied (applied) from the high-frequency power source320 to the electrode 300. The O₂ gas supplied into the process chamber201 is excited in a plasma state in the process chamber 201, is suppliedto the wafer 200 as active species (O*, O₂*), and is exhausted from theexhaust pipe 231. The O₂ gas excited in the plasma state will bereferred to as oxygen plasma.

The supply flow rate of the O₂ gas controlled by the MFC 241 b may beset at a flow rate which falls within a range of, for example, 100 sccmor more and 10,000 sccm or less. The high-frequency power applied fromthe high-frequency power source 320 to the electrode 300 may be set atelectric power which falls within a range of, for example, 50 W or moreand 1,000 W or less. The internal pressure of the process chamber 201may be set at a pressure which falls within a range of, for example, 10Pa or more and 300 Pa or less. By using the plasma, it is possible toactivate the O₂ gas even when the internal pressure of the processchamber 201 is in a relatively low pressure zone. The time, during whichthe active species obtained by plasma-exciting the O₂ gas are suppliedto the wafer 200, may be set at a time which falls within a range of,for example, 1 second or more and 100 seconds, or 1 second or more and50 seconds or less. Other processing conditions may be similar to theprocessing conditions of step S3 described above.

Ions generated in the oxygen plasma and electrically neutral activespecies are subjected to an oxidizing process as described hereinbelowon the Si-containing layer formed on the surface of the wafer 200.

By supplying the O₂ gas to the wafers 200 under the aforementionedconditions, the Si-containing layer formed on the wafers 200 isplasma-oxidized. At this time, Si—N bonds and Si—H bonds contained inthe Si-containing layer are broken by the energy of the plasma-excitedO₂ gas. N, H, and C bonded to N whose bonds with Si are broken aredelaminated from the Si-containing layer. Then, Si in the Si-containinglayer, which has dangling bonds due to delamination of N and the like,is bonded to O contained in the O₂ gas to form a Si—O bond. As thisreaction proceeds, the Si-containing layer can be changed (modified) toa layer containing Si and O, i.e., a silicon oxide layer (SiO layer).

Further, in order to modify the Si-containing layer to the SiO layer, itis necessary to supply the O₂ gas by plasma-exciting it. This isbecause, even when the O₂ gas is supplied under a non-plasma atmosphere,the energy necessary to oxidize the Si-containing layer is insufficientin the aforementioned temperature zone and it is difficult to increase aSi—O bond by sufficiently delaminating N or C from the Si-containinglayer or sufficiently oxidizing the Si-containing layer.

After the Si-containing layer is changed to the SiO layer, the valve 243b is closed to stop the supply of the O₂ gas. Further, the supply of thehigh-frequency power to the electrode 300 is stopped. Then, the O₂ gasor the reaction byproduct, which remains within the process chamber 201,is removed from the process chamber 201 under the same processingprocedures and processing conditions as those of step S4 (S6). Thereaction gas supply step may not include step S6.

As the oxidizing agent, i.e., the O-containing gas for plasma-exciting,it may be possible to use, in addition to the O₂ gas, a nitrous oxide(N₂O) gas, a nitrogen monoxide (NO) gas, a nitrogen dioxide (NO₂) gas,an ozone (O₃) gas, a peroxidation hydrogen (H₂O₂) gas, water vapor(H₂O), an ammonium hydroxide (NH₄(OH)) gas, a carbon monoxide (CO) gas,a carbon dioxide (CO₂) gas, or the like.

As the inert gas, it may be possible to use, in addition to the N₂ gas,for example, various kinds of rare gases exemplified at step S4.

(Performing a Predetermined Number of Times: S7)

A cycle which sequentially and non-simultaneously, i.e.,non-synchronously, performs steps S3, S4, S5 and S6 described above isset as one cycle and this cycle is implemented a predetermined number oftimes (n times), namely once or more. Thus, a SiO film having apredetermined composition and a predetermined thickness can be formed onthe wafer 200. The aforementioned cycle may be repeated multiple times.That is, the thickness of the SiO layer formed in one cycle may be setsmaller than a desired thickness and the aforementioned cycle may berepeated multiple times until the thickness of the SiO film formed bylaminating the SiO layer becomes equal to the desired thickness in someembodiments.

(Atmospheric Pressure Return Step: S8)

After the aforementioned film-forming process is completed, the N₂ gasas an inert gas is supplied from the respective gas supply pipes 232 cand 232 d into the process chamber 201 and is exhausted from the exhaustpipe 231. Thus, the interior of the process chamber 201 is purged withthe inert gas, and the O₂ gas or the like, which remains within theprocess chamber 201, is removed from the interior of the process chamber201 (inert gas purge). Thereafter, the internal atmosphere of theprocess chamber 201 is substituted by the inert gas (inert gassubstitution). The internal pressure of the process chamber 201 isreturned to an atmospheric pressure (atmospheric pressure return: S8).

(Unloading Step: S9)

Thereafter, the seal cap 219 is moved down by the boat elevator 115 toopen the lower end of the manifold 209. The processed wafers 200supported on the boat 217 are unloaded from the lower end of themanifold 209 to the outside of the reaction tube 203 (boat unloading).After the boat unloading, the shutter 219 s is moved so that the lowerend opening of the manifold 209 is sealed by the shutter 219 s throughthe O-ring 220 c (shutter closing). The processed wafers 200 areunloaded to the outside of the reaction tube 203 and are subsequentlydischarged from the boat 217 (wafer discharging). Further, after thewafer discharging, the empty boat 217 may be carried into the processchamber 201.

The internal pressure of the furnace during the substrate processing iscontrolled in a range of 10 Pa or more and 300 Pa or less in someembodiments. This is because, when the internal pressure of the furnaceis lower than 10 Pa, the mean free path of gas molecules becomes longerthan the Debye length of the plasma, and the plasma directly makingcontact with the furnace wall becomes prominent, thus making itdifficult to prevent the generation of particles. In addition, when theinternal pressure of the furnace is higher than 300 Pa, the plasmageneration efficiency is saturated, and the plasma generation amountdoes not change even if the reaction gas is supplied. Further, thereaction gas is unnecessarily consumed and at the same time, thetransfer efficiency of plasma active species to the wafers becomes worseas the mean free path of gas molecules becomes shorter.

(3) Effects according to the Present Embodiment

According to the present embodiment, one or more effects as set forthbelow may be achieved.

(a) By setting the surface area of the electrodes to which an arbitrarypotential is applied to be twice or more the surface area of theelectrodes to which a reference potential is applied, it is possible toincrease the plasma generation amount or the plasma generationefficiency.

(b) By making the electrode of a nickel alloy material to which aluminumis added, it is possible to prevent the deterioration process of theelectrodes, and to prevent a reduction in plasma generation efficiencydue to a reduction in electrical conductivity.

(c) By setting the central angle of the electrode fixing jig to an arcshape of 30 degrees or more and 240 degrees or less and arranging theelectrodes, it is possible to prevent the interruption of the heatenergy from the heating device on the outer periphery of the electrodefixing jig to a minimum level so as not to affect the wafer processing.

While embodiments of the present disclosure have been specificallydescribed above, the present disclosure is not limited to theaforementioned embodiments but may be differently modified withoutdeparting from the spirit of the present disclosure.

Furthermore, for example, in the aforementioned embodiments, there hasbeen described an example in which a reactant is supplied after aprecursor is supplied. The present disclosure is not limited to thisconfiguration, and the supply order of the precursor and the reactantmay be reversed. That is, the precursor may be supplied after thereactant is supplied. By changing the supply order, it is possible tochange the quality or composition ratio of a film as formed.

In the aforementioned embodiments and the like, there has been describedan example in which a SiO film is formed on the wafer 200. The presentdisclosure is not limited to this configuration but may be applied to acase where a Si-based oxide film such as a silicon oxycarbide film (SiOCfilm), a silicon oxycarbonitride film (SiOCN film), a silicon oxynitridefilm (SiON film) or the like is formed on the wafer 200 in someembodiments.

For example, by using a nitrogen (N)-containing gas such as ammonia(NH₃) gas, a carbon (C)-containing gas such as a propylene (C₃H₆) gas, aboron (B)-containing gas such as a boron trichloride (BCl₃) gas, or thelike, other than or in addition to the aforementioned gases or thesegases, for example, a SiN film, a SiON film, a SiOCN film, a SiOC film,a SiCN film, a SiBN film, a SiBCN film, a BCN film, or the like can beformed. In addition, the order which allows each gas to flow may beappropriately changed. Even in the case where these films are formed,the films may be formed under the same processing conditions as those ofthe aforementioned embodiments, and the same effects as those of theaforementioned embodiments may be achieved. In these cases, the reactiongas described above may be used for the oxidizing agent as the reactiongas.

Furthermore, the present disclosure may be applied to a case where ametal-based oxide film or a metal-based nitride film containing a metalelement such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum(Ta), niobium (Nb), aluminum (Al), molybdenum (Mo), tungsten (W) or thelike is formed on the wafer 200 in some embodiments. That is, thepresent disclosure may be applied to a case where a TiO film, a TiOCfilm, a TiOCN film, a TiON film, a TiN film, a TiSiN film, a TiBN film,a TiBCN film, a ZrO film, a ZrOC film, a ZrOCN film, a ZrON film, a ZrNfilm, a ZrSiN film, a ZrBN film, a ZrBCN film, an HfO film an HfOC film,an HfOCN film, an HfON film, an HfN film, an HfSiN film, an HfBN film,an HfOCN film, a TaO film, a TaOC film, a TaOCN film, a TaON film, a TaNfilm, a TaSiN film, a TaBN film, a TaBCN film, an NbO film, an NbOCfilm, an NbOCN film, an NbON film, an NbN film, an NbSiN film, an NbBNfilm, an NbBCN film, an AlO film, an AlOC film, an AlOCN film, an AlONfilm, an AN film, an AlSiN film, an AlBN film, an AlBCN film, an MoOfilm, an MoOC film, an MoOCN film, an MoON film, an MoN film, an MoSiNfilm, an MoBN Film, an MoBCN film, a WO film, a WOC film, a WOCN film, aWON film, a WN film, a WSiN film, a WBN film, a WBCN film, or the likeis formed on the wafer 200 in some embodiments.

In these cases, as the precursor gas, it may be possible to use, forexample, a tetrakis (dimethylamino) titanium (Ti[N(CH₃)₂]₄,abbreviation: TDMAT) gas, a tetrakis (ethylmethylamino) hafnium(Ti[N(C₂H₅)(CH₃)]₄, abbreviation: TEMAH) gas, a tetrakis(ethylmethylamino) zirconium (Zr[N(C₂H₅)(CH₃)]₄, abbreviation: TEMAZ)gas, a trimethylaluminum (Al(CH₃)₃, abbreviation: TMA) gas, a titaniumtetrachloride (TiCl₄) gas, a hafnium Tetrachloride (HfCl₄) gas, or thelike.

That is, the present disclosure may be applied to a case where asemi-metal-based film containing a semi-metal element or a metal-basedfilm containing a metal element is formed in some embodiments. Theprocessing procedures and processing conditions of the film-formingprocess may be similar to the processing procedures and processingconditions of the film-forming process illustrated in the embodiments ormodifications described above. Even in these cases, the same effects asthose of the aforementioned embodiments may be achieved.

Recipes used in a film-forming process may be prepared individuallyaccording to the processing contents and may be stored in the memorydevice 121 c via a telecommunication line or the external memory device123. Moreover, at the start of various processes, the CPU 121 a mayselect an appropriate recipe from the recipes stored in the memorydevice 121 c according to the processing contents in some embodiments.Thus, it is possible for a single substrate processing apparatus to formthin films of various kinds, composition ratios, qualities andthicknesses universally and with enhanced reproducibility. In addition,it is possible to reduce an operator's burden and to quickly startvarious processes while avoiding an operation error.

The recipes mentioned above are not limited to newly-prepared ones butmay be prepared by, for example, modifying the existing recipes alreadyinstalled in the substrate processing apparatus. When modifying therecipes, the modified recipes may be installed in the substrateprocessing apparatus via a telecommunication line or a recording mediumstoring the recipes. In addition, the existing recipes already installedin the substrate processing apparatus may be directly modified byoperating the input/output device 122 of the existing substrateprocessing apparatus.

According to the present disclosure in some embodiments, it is possibleto provide a technique capable of performing uniform substrateprocessing while maintaining a capability to generate active species bya plasma electrode.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosures.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

What is claimed is:
 1. A substrate processing apparatus, comprising: areaction tube in which a substrate is processed; and a plurality ofelectrodes including a plurality of first electrodes to which apredetermined potential is applied and at least one second electrode towhich a reference potential is applied, wherein the at least one secondelectrode is arranged to be sandwiched between two sets of two or morecontinuously arranged electrodes of the plurality of first electrodes.2. The substrate processing apparatus according to claim 1, wherein aninterval between the at least one second electrode and the plurality offirst electrodes is equal to an interval between the two or morecontinuously arranged electrodes of the plurality of first electrodes.3. The substrate processing apparatus according to claim 1, wherein theplurality of electrodes is installed on an outer periphery of thereaction tube.
 4. The substrate processing apparatus according to claim1, wherein the plurality of electrodes is arranged in an order of one ofthe plurality of first electrodes, another one of the plurality of firstelectrodes, and one of the at least one second electrode.
 5. Thesubstrate processing apparatus according to claim 1, wherein a surfacearea of the plurality of first electrodes is two times or more than asurface area of the at least one second electrode.
 6. The substrateprocessing apparatus according to claim 1, further comprising anelectrode fixing portion configured to fix the plurality of electrodes.7. The substrate processing apparatus according to claim 6, furthercomprising a spacer configured to separate the plurality of electrodesfrom a surface of the electrode fixing portion by a predetermineddistance, wherein the plurality of electrodes includes a bent portion,and the spacer is configured to make contact with a valley of the bentportion.
 8. The substrate processing apparatus according to claim 6,wherein the electrode fixing portion is a quartz cover made of quartz.9. The substrate processing apparatus according to claim 6, wherein theelectrode fixing portion is disposed on an outer periphery of thereaction tube other than positions at which a gas supplier and a gasexhauster installed in the reaction tube are installed.
 10. Thesubstrate processing apparatus according to claim 6, further comprisinga heating device installed outside the electrode fixing portion andconfigured to heat the substrate.
 11. The substrate processing apparatusaccording to claim 10, wherein the plurality of electrodes is installedbetween the reaction tube and the heating device.
 12. The substrateprocessing apparatus according to claim 10, wherein the plurality ofelectrodes is installed between the electrode fixing portion and theheating device.
 13. The substrate processing apparatus according toclaim 1, wherein the plurality of electrodes is made of a nickel alloymaterial to which aluminum is added.
 14. The substrate processingapparatus according to claim 1, wherein the plurality of electrodes isconfigured to form plasma in the reaction tube.
 15. The substrateprocessing apparatus according to claim 14, further comprising a gassupplier configured to supply gas to the reaction tube.
 16. Thesubstrate processing apparatus according to claim 15, wherein the gas isactivated by the plasma.
 17. The substrate processing apparatusaccording to claim 14, wherein the plasma is a capacitively coupledplasma.
 18. A plurality of electrodes, comprising: a plurality of firstelectrodes to which a predetermined potential is applied and at leastone second electrode to which a reference potential is applied, whereinthe at least one second electrode is arranged to be sandwiched betweentwo or more continuously arranged electrodes of the plurality of firstelectrodes.
 19. A method of manufacturing a semiconductor device,comprising: loading a substrate into a reaction tube of a substrateprocessing apparatus which includes: the reaction tube in which thesubstrate is processed; a plurality of first electrodes to which apredetermined potential is applied; and at least one second electrode towhich a reference potential is applied, wherein the at least one secondelectrode is arranged to be sandwiched between two or more continuouslyarranged electrodes of the plurality of first electrodes; and processingthe substrate.